Anti-migration stent

ABSTRACT

An illustrative stent may comprise an elongated tubular member having a first end and a second end and an intermediate region disposed therebetween. The elongated tubular member may include at least one flexible tie affixed to an end thereof. The tie may allow the stent to be attached to a lumen wall with a clip, such as a retention clip, to inhibit migration of the stent within the body lumen.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application No. 62/113,126, filed Feb. 6, 2015, the entiredisclosure of which is herein incorporated by reference.

TECHNICAL FIELD

The present disclosure pertains to medical devices, and methods formanufacturing medical devices. More particularly, the present disclosurepertains to an anti-migration stent.

BACKGROUND

Implantable stents are devices that are placed in a body structure, suchas a blood vessel or body cavity, to provide support and to maintain thestructure open. These devices are manufactured by any one of a varietyof different manufacturing methods and may be used according to any oneof a variety of methods. Of the known medical devices, delivery systems,and methods, each has certain advantages and disadvantages. There is anongoing need to provide alternative medical devices and delivery devicesas well as alternative methods for manufacturing and using medicaldevices and delivery devices.

BRIEF SUMMARY

This disclosure provides design, material, manufacturing method, and usealternatives for medical devices. An example medical device may includea stent. The stent comprises:

-   -   an elongated tubular member having a first end, a second end and        an intermediate region disposed therebetween, the elongated        tubular member comprising at least one filament; and    -   at least one flexible tie attached to the filament adjacent to        the first end of the tubular member, the flexible tie having a        first end and a second end.

Alternatively or additionally to any of the embodiments above, the firstend of the flexible tie includes a first aperture and the second end ofthe flexible tie includes a second aperture.

Alternatively or additionally to any of the embodiments above, the stentfurther comprises an intermediate region disposed between the firstaperture and the second aperture of the tie.

Alternatively or additionally to any of the embodiments above, theflexible tie comprises a single loop.

Alternatively or additionally to any of the embodiments above, theflexible tie is knotted to the filament of the tubular member.

Alternatively or additionally to any of the embodiments above, theflexible tie is adhesively secured to the filament of the tubularmember.

Alternatively or additionally to any of the embodiments above, the atleast one flexible tie comprises two or more flexible ties.

Alternatively or additionally to any of the embodiments above, the atleast one flexible tie is biodegradable.

Alternatively or additionally to any of the embodiments above, the stentfurther comprises at least one clip configured to be secured to the atleast one flexible tie.

Alternatively or additionally to any of the embodiments above, the clipcomprises a pair of jaws configured to clamp around the at least oneflexible tie.

An example kit for securing a stent comprises:

-   -   a stent having a first end, a second end and an intermediate        region disposed therebetween;    -   at least one flexible tie; and    -   at least one clip.

Alternatively or additionally to any of the embodiments above, theflexible tie comprises a single loop.

Alternatively or additionally to any of the embodiments above, a firstportion of the single loop is secured to a second portion of the singleloop to define a first aperture and a second aperture.

Alternatively or additionally to any of the embodiments above, the clipcomprises a pair of jaws.

Alternatively or additionally to any of the embodiments above, the clipcomprises a hemostasis clip, such as, but not limited to the Resolution®Clip made by Boston Scientific, Corporation.

Alternatively or additionally to any of the embodiments above, whereinthe flexible tie is secured to the stent adjacent to the first end ofthe stent.

Another example system for reducing migration of a stent comprises:

-   -   an elongated tubular member having a first end, a second end and        an intermediate region disposed therebetween, the elongated        tubular member comprising at least one woven filament;    -   a retainer; and    -   at least one tie extending between the elongated tubular member        and the retainer.

Alternatively or additionally to any of the embodiments above, theretainer comprises at least one aperture for receiving the at least onetie.

Alternatively or additionally to any of the embodiments above, the atleast one tie comprises a distal end including a clip, the clipconfigured to secure the tie to the tubular member.

Alternatively or additionally to any of the embodiments above, the clipcomprise a pair of jaws configured to clasp the tubular member.

Alternatively or additionally to any of the embodiments above, theretainer comprises a “U”-shape.

The above summary of some embodiments is not intended to describe eachdisclosed embodiment or every implementation of the present disclosure.The Figures, and Detailed Description, which follow, more particularlyexemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of thefollowing detailed description of various embodiments in connection withthe accompanying drawings, in which:

FIG. 1 is a side view of an illustrative anti-migration stent.

FIG. 2A is a side view of an illustrative tie.

FIG. 2B is a close up view of an end portion of an illustrativeanti-migration stent.

FIG. 2C a close up view of an end portion of the illustrativeanti-migration stent of FIG. 2B including a fixation mechanism, such asa hemostasis clip device.

FIG. 3A is a close up view of an end portion of another illustrativeanti-migration stent.

FIG. 3B a close up view of an end portion of the illustrativeanti-migration stent of FIG. 3A including a fixation mechanism.

FIG. 4A is a perspective view of another illustrative stent fixationmechanism.

FIG. 4B is a perspective view of the illustrative stent fixationmechanism of FIG. 4A and an illustrative stent.

FIG. 5 is a side view of another illustrative anti-migration stent.

While the disclosure is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit aspects of theinvention to the particular embodiments described. On the contrary, theintention is to cover all modifications, equivalents, and alternativesfalling within the scope of the invention.

DETAILED DESCRIPTION

For the following defined terms, these definitions shall be applied,unless a different definition is given in the claims or elsewhere inthis specification.

All numeric values are herein assumed to be modified by the term“about”, whether or not explicitly indicated. The term “about” generallyrefers to a range of numbers that one of skill in the art would considerequivalent to the recited value (i.e., having the same function orresult). In many instances, the term “about” may be indicative asincluding numbers that are rounded to the nearest significant figure.

The recitation of numerical ranges by endpoints includes all numberswithin that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4,and 5).

Although some suitable dimensions ranges and/or values pertaining tovarious components, features and/or specifications are disclosed, one ofskill in the art, incited by the present disclosure, would understanddesired dimensions, ranges and/or values may deviate from thoseexpressly disclosed.

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include plural referents unless the contentclearly dictates otherwise. As used in this specification and theappended claims, the term “or” is generally employed in its senseincluding “and/or” unless the content clearly dictates otherwise.

The following detailed description should be read with reference to thedrawings in which similar elements in different drawings are numberedthe same. The detailed description and the drawings, which are notnecessarily to scale, depict illustrative embodiments and are notintended to limit the scope of the invention. The illustrativeembodiments depicted are intended only as exemplary. Selected featuresof any illustrative embodiment may be incorporated into an additionalembodiment unless clearly stated to the contrary.

In some instances, it may be desirable to provide an endoluminalimplant, or stent, that can deliver luminal patency in patients withesophageal strictures. Such stents may be used in patients experiencingdysphagia, sometimes due to esophageal cancer. An esophageal stent mayallow a patient to maintain nutrition via oral intake during cancertreatment or palliation periods. However, a common complication ofgastrointestinal (GI) stents is stent migration. It may be desirable toprovide a stent that can deliver luminal patency while minimizingmigration of the stent. While the embodiments disclosed herein arediscussed with reference to esophageal stents, it is contemplated thatthe stents described herein may be used and sized for use in otherlocations such as, but not limited to: bodily tissue, bodily organs,vascular lumens, non-vascular lumens and combinations thereof, such as,but not limited to, in the coronary or peripheral vasculature, trachea,bronchi, colon, small intestine, biliary tract, urinary tract, prostate,brain, stomach and the like.

FIG. 1 illustrates a side view of an illustrative endoluminal implant10, such as, but not limited to, a stent. In some instances, the stent10 may be formed from an elongated tubular member 12. While the stent 10is described as generally tubular, it is contemplated that the stent 10may take any cross-sectional shape desired. The stent 10 may have afirst, or proximal, end 14, a second, or distal, end 16, and anintermediate region 18 disposed between the first end 14 and the secondend 16. The stent 10 may include a lumen 32 extending from a firstopening adjacent the first end 14 to a second opening adjacent to thesecond end 16 to allow for the passage of food, fluids, etc.

The stent 10 may be expandable from a first collapsed configuration (notexplicitly shown) to a second expanded configuration. The stent 10 maybe structured to extend across a stricture and to apply a radiallyoutward pressure to the stricture in a lumen to open the lumen and allowfor the passage of foods, fluids, air, etc.

The stent 10 may have a woven structure, fabricated from a number offilaments or struts 36. In some embodiments, the stent 10 may be braidedwith one filament. In other embodiments, the stent 10 may be braidedwith several filaments, as is found, for example, in the WallFlex®,WALLSTENT®, and Polyflex® stents, made and distributed by BostonScientific, Corporation. In another embodiment, the stent 10 may beknitted, such as the Ultraflex™ stents made by Boston Scientific,Corporation. In yet another embodiment, the stent 10 may be of a knottedtype, such the Precision Colonic™ stents made by Boston Scientific,Corporation. In still another embodiment, the stent 10 may be a lasercut tubular member, such as the EPIC™ stents made by Boston Scientific,Corporation. A laser cut tubular member may have an open and/or closedcell geometry including one or more interconnected filaments. In someinstances, an inner and/or outer surface of the stent 10 may beentirely, substantially or partially, covered with a polymeric coveringor coating. For example, a covering or coating which may help reducefood impaction and/or tumor or tissue ingrowth.

In some instances, in the expanded configuration, the stent 10 mayinclude a first end region 20 and a second end region 22. In someembodiments, the first end region 20 and the second end region 22 mayinclude retention features or anti-migration flared regions 24, 26positioned adjacent to the first end 14 and the second end 16 of thestent 10. The anti-migration flared regions 24, 26 may be configured toengage an interior portion the walls of the esophagus. In someembodiments, the retention features, or flared regions 24, 26 may have alarger diameter than an intermediate region 18 of the stent 10 toprevent the stent 10 from migrating once placed in the esophagus. It iscontemplated that the transition 28, 30 from the cross-sectional area ofthe intermediate region 18 to the retention features or flared regions24, 26 may be gradual, sloped, or occur in an abrupt step-wise manner,as desired.

In some embodiments, the first anti-migration flared region 24 may havea first outer diameter and the second anti-migration flared region 26may have a second outer diameter. In some instances, the first andsecond outer diameters may be approximately the same, while in otherinstances, the first and second outer diameters may be different. Insome embodiments, the stent 10 may include only one or none of theanti-migration flared regions 24, 26. For example, the first end region20 may include an anti-migration flare 24 while the second end region 22may have an outer diameter similar to the intermediate region 18. It isfurther contemplated that the second end region 22 may include ananti-migration flare 26 while the first end region 20 may have an outerdiameter similar to an outer diameter of the intermediate region 18. Insome embodiments, the stent 10 may have a uniform outer diameter fromthe first end 14 to the second end 16. In some embodiments, the outerdiameter of the intermediate region 18 may be in the range of 15 to 25millimeters. The outer diameter of the anti-migration flares 24, 26 maybe in the range of 20 to 30 millimeters. It is contemplated that theouter diameter of the stent 10 may be varied to suit the desiredapplication.

It is contemplated that the stent 10 can be made from a number ofdifferent materials such as, but not limited to, metals, metal alloys,shape memory alloys and/or polymers, as desired, enabling the stent 10to be expanded into shape when accurately positioned within the body. Insome instances, the material may be selected to enable the stent 10 tobe removed with relative ease as well. For example, the stent 10 can beformed from alloys such as, but not limited to, nitinol and Elgiloy®.Depending the on material selected for construction, the stent 10 may beself-expanding or require an external force to expand the stent 10. Insome embodiments, fibers may be used to make the stent 10, which may becored fibers, for example, having an outer shell made of nitinol havinga platinum core. It is further contemplated the stent 10 may be formedfrom polymers including, but not limited to, polyethylene terephthalate(PET).

The stent 10 may further include one or more ties (e.g., sutures ortethers 34) attached adjacent to the first end 14 of the stent 10. Aswill be discussed in more detail below, the ties 34 may allow aphysician to attach one or more fixation mechanisms or retention clipssimultaneously to the ties 34 and the body lumen. In some instances, thefixation mechanism may be a hemostasis clip, such as, but not limited tothe Resolution® Clip made by Boston Scientific, Corporation, While thefixation mechanism is described as a clip, it is contemplated that anystructure that allows for attachment of the tie 34 to the lumen wall maybe used to secure the tie 34 within the lumen. It is contemplated thatthe one or more ties 34 may be attached to the stent 10 at any pointalong the length thereof. For example, in some embodiments, the ties 34may be affixed adjacent to the intermediate region 18 while in otherinstances, the ties 34 may be affixed adjacent to the second end 16.This may allow the stent 10 to be anchored such that proximal, distal,or both proximal and distal movement is prevented. In some embodiments,the ties 34 may be provided in a kit including the stent 10 and clips.In some instances, the stent 10 may be delivered with the ties 34previously attached thereto. This may allow a physician to attach thedesired number of ties 34 to the stent 10 prior to use. A kit may alsoinclude a stent 10 with attached ties 34 and one or more clips. Whilethe stent 10 is shown as having two ties 34, it is contemplated that thestent 10 may include any number of ties 34 desired, such as, but notlimited to, one, two, three, four, or more. The ties 34 may be made of aflexible, bendable material. In some instances, the ties 34 may beformed from suture material, or other biocompatible material. It iscontemplated that the ties 34 may be formed from a biodegradablematerial that may “fall away” or be absorbed by the patient's body aftera period of time, such as two to three weeks after the stent 10 isplaced.

The ties 34 may include a first end 38, a second end 40, and anintermediate region 42 disposed therebetween. The first end 38 mayinclude a loop or other structure that allows a clamp, clip or otherretention mechanism to grasp a portion of the tie. In some embodiments,the first end 38 may be a solid or substantially solid enlarged portionthat provides a surface area for the clip to grasp. In otherembodiments, the first end 38 may have a substantially “T” shape thatprovides a region for the clip to grasp. The second end 40 of the tie 34may be affixed to a filament/strut 36 of the stent 10. It iscontemplated that the second end 40 may be affixed or attached to thestent 10 in a number of suitable ways. For example, the tie 34 may beadhesively secured to the stent 10 or the tie 34 may be knotted, looped,or wound about a filament 36. The intermediate region 42 of the tie 34may be any length desired to provide a physician with easy access toattach a clip to the first end 38 of the tie 34. While the ties 34 areillustrated as having a similar length, it is contemplated that the ties34 may have differing lengths to allow for staggering of the clips, ifdesired.

The second end 40 of the tie 34 may be secured to the stent 10 such thatthe tie 34 extends beyond or is capable of extending beyond the tubularportion 12 of the stent 10. For example, as shown in FIG. 1, the tie 34may be secured adjacent to the proximal end 14 of the stent 10 andextend proximally therefrom. While not explicitly shown, it iscontemplated that the tie 34 may be secured adjacent to the distal end15 of the stent 10 and extend distally therefrom. When a clip is used tosecure the stent 10 within a lumen, the tie 34 may be moved away fromthe tubular portion 12 of the stent 10 to allow the physician to easilysecure a portion of the tissue and the tie 34 within the securingmechanism. As will be described in more detail below, if a physicianchooses not to use one or more of the ties 34, the tie(s) 34 may beallowed to hang from the stent 10. In some instances, gravity may drawthe ties(s) 34 into the lumen 32 of the stent 10 when they are notsecured with a retention mechanism or clip.

Referring additionally to FIG. 5, which illustrates a side view ofanother illustrative endoluminal implant 400, such as, but not limitedto, a stent. The stent 400 may be similar in form and function to thestent 10 described above. In some instances, the stent 400 may be formedfrom an elongated tubular member 412. While the stent 400 is describedas generally tubular, it is contemplated that the stent 400 may take anycross-sectional shape desired. The stent 400 may have a first end 414,such as a proximal end, a second end 416, such as a distal end, and anintermediate region 418 disposed between the first end 414 and thesecond end 416. The stent 400 may include a lumen 432 extending from afirst opening adjacent the first end 414 to a second opening adjacent tothe second end 416 to allow for the passage of food, fluids, etc.

The stent 400 may be expandable from a first collapsed configuration(not explicitly shown) to a second expanded configuration. The stent 400may be structured to extend across a stricture and to apply a radiallyoutward pressure to the stricture in a lumen to open the lumen and allowfor the passage of foods, fluids, air, etc.

In some embodiments, the stent 400 may have a woven structure,fabricated from a number of filaments or struts 436. In anotherembodiment, the stent 400 may be a laser cut tubular member. In someinstances, an inner and/or outer surface of the stent 400 may beentirely, substantially or partially, covered with a polymeric coveringor coating. For example, a covering or coating which may help reducefood impaction and/or tumor or tissue ingrowth.

In some instances, in the expanded configuration, the stent 400 mayinclude a first end region 420 and a second end region 422. In someembodiments, the first end region 420 and the second end region 422 mayinclude retention features or anti-migration flared regions 424, 426positioned adjacent to the first end 414 and the second end 416 of thestent 400. The anti-migration flared regions 424, 426 may be configuredto engage an interior portion the walls of the body lumen, such as theesophagus. In some embodiments, the retention features, or flaredregions 424, 426 may have a larger diameter than an intermediate region418 of the stent 400 to prevent the stent 400 from migrating once placedin the body lumen, such as the esophagus. It is contemplated that thetransition 428, 430 from the cross-sectional area of the intermediateregion 418 to the retention features or flared regions 424, 426 may begradual, sloped, or occur in an abrupt step-wise manner, as desired.

In some embodiments, the first anti-migration flared region 424 may havea first outer diameter and the second anti-migration flared region 426may have a second outer diameter. In some instances, the first andsecond outer diameters may be approximately the same, while in otherinstances, the first and second outer diameters may be different. Insome embodiments, the stent 400 may include only one or none of theanti-migration flared regions 424, 426. In some embodiments, the stent400 may have a uniform outer diameter from the first end 414 to thesecond end 416. In some embodiments, the outer diameter of theintermediate region 418 may be in the range of 15 to 25 millimeters. Theouter diameter of the anti-migration flares 424, 426 may be in the rangeof 20 to 30 millimeters. It is contemplated that the outer diameter ofthe stent 400 may be varied to suit the desired application.

It is contemplated that the stent 400 can be made from a number ofdifferent materials such as, but not limited to, metals, metal alloys,shape memory alloys and/or polymers, as desired, enabling the stent 400to be expanded into shape when accurately positioned within the body. Insome instances, the material may be selected to enable the stent 400 tobe removed with relative ease as well. For example, the stent 400 can beformed from alloys such as, but not limited to, nitinol and Elgiloy®.Depending the on material selected for construction, the stent 400 maybe self-expanding or require an external force to expand the stent 400.In some embodiments, fibers may be used to make the stent 400, which maybe cored fibers, for example, having an outer shell made of nitinolhaving a platinum core. It is further contemplated the stent 400 may beformed from polymers including, but not limited to, polyethyleneterephthalate (PET).

The stent 400 may further include one or more ties (e.g., sutures ortethers 434) attached to the tubular member 412, such as adjacent to thefirst end 414 of the stent 400. As will be discussed in more detailbelow, the ties 434 may allow a physician to attach one or more fixationmechanisms or clips simultaneously to the ties 434 and the body lumen.In some instances, the fixation mechanism may be a hemostasis clip, suchas, but not limited to the Resolution® Clip made by Boston Scientific,Corporation, While the fixation mechanism is described as a clip, it iscontemplated that any structure that allows for attachment of the tie434 to the lumen wall may be used to secure the tie 434 within thelumen. While the illustrative embodiment illustrates ties 434 attachedto both the first and second ends 414, 416, it is contemplated that theone or more ties 434 may be attached to the stent 400 at any point alongthe length thereof. For example, in some embodiments, the ties 434 maybe affixed adjacent to the intermediate region 418 while in otherinstances, the ties 434 may be affixed adjacent to either the first end414 or the second end 416, but not both. This may allow the stent 400 tobe anchored such that proximal, distal, or both proximal and distalmovement is prevented. In some embodiments, the ties 434 may be providedin a kit including the stent 400 and clips. In some instances, the stent400 may be delivered with the ties 434 previously attached thereto. Thismay allow a physician to attach the desired number of ties 434 to thestent 400 prior to use. A kit may also include a stent 400 with attachedties 434 and one or more clips. While the stent 400 is shown as havingfour ties 434, it is contemplated that the stent 400 may include anynumber of ties 434 desired, such as, but not limited to, one, two,three, four, or more. The ties 434 may be made of a flexible, bendablematerial. In some instances, the ties 434 may be formed from suturematerial, or other biocompatible material. It is contemplated that theties 434 may be formed from a biodegradable material that may “fallaway” or be absorbed by the patient's body after a period of time, suchas two to three weeks after the stent 400 is placed.

The ties 434 may include a first end 438, a second end 440, and anintermediate region 442 disposed therebetween. The first end 438 mayinclude a loop or other structure that allows a clamp, clip or otherretention mechanism to grasp a portion of the tie. In some embodiments,the first end 438 may be a solid or substantially solid enlarged portionthat provides a surface area for the clip to grasp. In otherembodiments, the first end 438 may have a substantially “T” shape thatprovides a region for the clip to grasp. The second end 440 of the tie434 may be affixed to a filament/strut 436 of the stent 400. It iscontemplated that the second end 40 may be affixed or attached to thestent 400 in a number of suitable ways. For example, the tie 434 may beadhesively secured to the stent 400 or the tie 434 may be knotted,looped, or wound about a filament 436. The intermediate region 442 ofthe tie 434 may be any length desired to provide a physician with easyaccess to attach a clip to the first end 438 of the tie 434. While theties 434 are illustrated as having a similar length, it is contemplatedthat the ties 434 may have differing lengths to allow for staggering ofthe clips, if desired.

The second end 440 of the tie 434 may be secured to the stent 400 suchthat the tie 434 extends beyond or is capable of extending beyond thetubular portion 412 of the stent 400. For example, as shown in FIG. 5,one or more ties 434 may be secured adjacent to the proximal end 414 ofthe stent 400 and extend proximally therefrom and one or more ties 434may be secured adjacent to the distal end 416 of the stent and extenddistally therefrom. When a clip is used to secure the stent 400 within alumen, the tie 434 may be moved away from the tubular portion 412 of thestent 400 to allow the physician to easily secure a portion of thetissue and the tie 434 within the securing mechanism. As will bedescribed in more detail below, if a physician chooses not to use one ormore of the ties 434, the tie(s) 434 may be allowed to hang from thestent 400. In some instances, gravity may draw the ties(s) 434 into thelumen 432 of the stent 400 when they are not secured with a retentionmechanism or clip.

Referring now to FIG. 2A, which illustrates a close up view of anillustrative tie 134, the tie 134 may include a first looped end 138having a first opening or aperture 144 and a second looped end 140having a second opening or aperture 146. The first looped end 138 andthe second looped end 140 may be connected by an intermediate region142. In some instances, the tie 134 may be formed as a unitarystructure. For example, the tie 134 may be formed as a single loop withportions of the loop 148 secured together along the intermediate region142 to form the first opening 144 and the second opening 146. In otherinstances, the tie 134 may be formed of separate components secured toone another. For example, one or more of the first looped end 138,second looped end 140, to and/or the intermediate region 142 may beformed as an individual component and secured to the remainingcomponents, as desired. In yet another embodiment, the tie 134 may beformed as a generally solid rectangular or oblong structure. One or moreslits may be made in the rectangular structure adjacent to the first endand the second end thereof to form the first opening 144 and the secondopening 146. It is contemplated that the tie 134 may be formed in anymanner that allows it to be secured to a stent, such as stent 10, and toa clip. In some embodiments, the tie 134 may be provided with a clip,clamp, or other mechanism configured to grasp or surround a portion ofthe stent 10.

FIG. 2B is a close up side view of an illustrative stent 10 with a tie134 secured adjacent to the first end 14 of the stent 10. The tie 134may be looped around a filament 36 of the stent 10 to secure the tie 134to the stent 10. For example, the tie 134 may be placed on a first side(for example, an inner or outer surface) of the filament 36. The firstlooped end 138 may be wound or wrapped around the filament 36 on thesecond side. The first looped end 138 may be pushed through the secondopening 146 and pulled to form a knot 160 and secure the tie 134 to thestent 10 in a looped manner, as illustrated in FIG. 2B. In someinstances, an adhesive may be used in addition to, or in place of, theknot 160.

FIG. 2C is a close up side view of an illustrative stent 10 with a tie134 secured adjacent to the first end 14 of the stent 10 and anillustrative clip 150 affixed to the tie 134. The stent 10 may bedelivered and deployed to the target location using a stent deliverysystem and/or an endoscope, gastroscope or other guide means (notexplicitly shown). The stent 10 may be advanced to the target locationin a collapsed configuration and then expanded into an enlargedconfiguration. In some instances, it may be desirable to attach thestent 10 to the lumen to reduce or prevent migration of the stent 10.When a 150 clip is used to secure the stent 10 within a lumen, the tie134 may be moved away from the tubular portion 12 of the stent 10 toallow the physician to easily secure a portion of the tissue and the tie134 within the securing mechanism. For example, the tie 134 may extendproximally from the proximal end 14 of the stent 10 and be secured tothe body lumen proximal of the proximal end 14 of the stent. In anesophageal application, this may reduce distal migration or movement ofthe stent 10. This is just an example. In other applications, it may bedesirable to secure a tie 134 distal of the distal end of the stent 10to prevent proximal migration, for example. The physician may use a clip150 to grip both a portion of the tie 134 (e.g., the first looped end138 of the tie 134) and tissue of the lumen thus securing the stent 10within the lumen. If a physician chooses not to use one or more of theties 134, the tie 134 may hang, or be otherwise disposed, within thelumen 32 of the stent 10. The physician may choose to use as many clips150 and/or ties 134 as they feel necessary to prevent migration of thestent 10. In some instances, more than one clip 150 may be used with asingle tie 134. The clip 150 may include a pair of jaws 152 that may beopened and closed to grasp the tie 134 and tissue therebetween. In someinstances, the jaws 152 may be able to open and close a number of timesprior to deploying the clip 150 to aid in positioning and/orrepositioning of the clip 150. While not explicitly shown, the clip 150may include a delivery system configured to advance the clip 150, openand close the jaws 152, and deploy the clip 150 within the lumen. Theclip 150 may be left in place with the stent 10 or may be removed aftera period of time. For example, the clip(s) 150 may be removed aftertissue ingrowth has secured the stent 10 in place.

FIG. 3A is a close up side view of an illustrative stent 10 with anotherillustrative tie 234 secured adjacent to the first end 14 of the stent10. The tie 234 may be formed of a single loop of material, similar to arubber band, defining an opening 244. The tie 234 may be looped around afilament 36 of the stent 10 to secure the tie 234 to the stent 10. Forexample, the tie 234 may be placed on a first side (for example, aninner or outer surface) of the filament 36. A first end 238 may be woundor wrapped around the filament 36 on the second side. The first end 238may be pushed through the opening 246 adjacent to the second end 240 andpulled to form a knot 260 and secure the tie 234 to the stent 10 in alooped manner, as illustrated in FIG. 3A. In some instances, an adhesivemay be used in addition to, or in place of, the knot 260.

FIG. 3B is a close up side view of an illustrative stent 10 with a tie234 secured adjacent to the first end 14 of the stent 10 and anillustrative clip 250 affixed to the tie 234. The stent 10 may bedelivered and deployed to the target location using a stent deliverysystem and/or an endoscope, gastroscope or other guide means (notexplicitly shown). The stent 10 may be advanced to the target locationin a collapsed configuration and then expanded into an enlargedconfiguration. In some instances, it may be desirable to attach thestent 10 to the lumen to reduce or prevent migration of the stent 10.The physician may use a clip 150 to grip both the tie 134 and tissue ofthe lumen thus securing the stent 10 within the lumen. If a physicianchooses not to use one or more of the ties 234, the tie 234 may hang, orbe otherwise disposed, within the lumen 32 of the stent 10. Thephysician may choose to use as many clips 150 and/or ties 234 as theyfeel necessary to prevent migration of the stent 10. In some instances,more than one clip 150 may be used with a single tie 234. The clip 150may include a pair of jaws 152 that may be opened and closed to graspthe tie 234 and tissue therebetween. In some instances, the jaws 152 maybe able to open and close a number of times prior to deploying the clip150 to aid in positioning and/or repositioning of the clip 150. Whilenot explicitly shown, the clip 150 may include a delivery systemconfigured to advance the clip 150, open and close the jaws 152, anddeploy the clip 150 within the lumen.

FIGS. 4A and 4B illustrate another illustrative system 350 for reducingand/or preventing migration of an esophageal stent, such as stent 310.The stent 310 may be similar in form and function to the stent 10described above. The system 350 may be a mandible system configured tobe placed in a patient's mouth. The system 350 may include a retainer352 sized and shaped to be positioned over a patient's bottom teeth. Theretainer 352 may be generally “U”-shaped having a first leg 354 and asecond leg 356. The first and second legs 354, 356 may each include anaperture 358, 360 extending therethrough. Alternatively, only one of thelegs 354, 356 may include an aperture 358, 360. In some instances, theapertures may be positioned such along the retainer 352 such that theyare near the back of a patient's mouth when the retainer is in apatient's mouth. One or more tethers or ties 362 may be attached to theapertures 358, 360. The ties 362 may be knotted, wound, wrapped,adhesively secured, or otherwise secured to the retainer 352. The ties362 may be made of a flexible, bendable material. In some instances, theties 362 may be formed from suture material, or other biocompatiblematerial. It is contemplated that the ties 362 may be formed from abiodegradable material that may “fall away” or be absorbed by thepatient's body after a period of time, such as two to three weeks aftera stent is placed. Each of the ties 362 may include a clamp or clip 364disposed adjacent a distal end 368 thereof. The clip 364 may include apair of jaws 370 capable of opening and closing. In some instances theclip 364 may include a spring to bias the jaws 370 toward a closedposition to grip tissue, etc. therebetween. The jaws 370 may clasparound a portion of a stent 310, such as a filament 336, to secure thetie 362 to the stent 310. Alternatively, the tie 362 may be tied to,knotted around or adhesively secured to the stent 310. It iscontemplated that the retainer 352 may be removed from a patient's mouthafter a period of time, such as but not limited, one week, or until thestent 310 is set in place on its own. The ties 362 may be disconnected(for example, untied, cut, etc.) and allowed to drop or hang from thestent 310.

The stents, delivery systems, and the various components thereof, may bemade from a metal, metal alloy, polymer (some examples of which aredisclosed below), a metal-polymer composite, ceramics, combinationsthereof, and the like, or other suitable material. Some examples ofsuitable metals and metal alloys include stainless steel, such as 304V,304L, and 316LV stainless steel; mild steel; nickel-titanium alloy suchas linear-elastic and/or super-elastic nitinol; other nickel alloys suchas nickel-chromium-molybdenum alloys (e.g., UNS: N06625 such as INCONEL®625, UNS: N06022 such as HASTELLOY® C-22®, UNS: N10276 such asHASTELLOY® C276®, other HASTELLOY® alloys, and the like), nickel-copperalloys (e.g., UNS: N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS®400, and the like), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035 such as MP35-N® and the like), nickel-molybdenum alloys (e.g.,UNS: N10665 such as HASTELLOY® ALLOY B2®), other nickel-chromium alloys,other nickel-molybdenum alloys, other nickel-cobalt alloys, othernickel-iron alloys, other nickel-copper alloys, other nickel-tungsten ortungsten alloys, and the like; cobalt-chromium alloys;cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as ELGILOY®,PHYNOX®, and the like); platinum enriched stainless steel; titanium;combinations thereof; and the like; or any other suitable material.

As alluded to herein, within the family of commercially availablenickel-titanium or nitinol alloys, is a category designated “linearelastic” or “non-super-elastic” which, although may be similar inchemistry to conventional shape memory and super elastic varieties, mayexhibit distinct and useful mechanical properties. Linear elastic and/ornon-super-elastic nitinol may be distinguished from super elasticnitinol in that the linear elastic and/or non-super-elastic nitinol doesnot display a substantial “superelastic plateau” or “flag region” in itsstress/strain curve like super elastic nitinol does. Instead, in thelinear elastic and/or non-super-elastic nitinol, as recoverable strainincreases, the stress continues to increase in a substantially linear,or a somewhat, but not necessarily entirely linear relationship untilplastic deformation begins or at least in a relationship that is morelinear that the super elastic plateau and/or flag region that may beseen with super elastic nitinol. Thus, for the purposes of thisdisclosure linear elastic and/or non-super-elastic nitinol may also betermed “substantially” linear elastic and/or non-super-elastic nitinol.

In some cases, linear elastic and/or non-super-elastic nitinol may alsobe distinguishable from super elastic nitinol in that linear elasticand/or non-super-elastic nitinol may accept up to about 2-5% strainwhile remaining substantially elastic (e.g., before plasticallydeforming) whereas super elastic nitinol may accept up to about 8%strain before plastically deforming. Both of these materials can bedistinguished from other linear elastic materials such as stainlesssteel (that can also can be distinguished based on its composition),which may accept only about 0.2 to 0.44 percent strain beforeplastically deforming.

In some embodiments, the linear elastic and/or non-super-elasticnickel-titanium alloy is an alloy that does not show anymartensite/austenite phase changes that are detectable by differentialscanning calorimetry (DSC) and dynamic metal thermal analysis (DMTA)analysis over a large temperature range. For example, in someembodiments, there may be no martensite/austenite phase changesdetectable by DSC and DMTA analysis in the range of about −60 degreesCelsius (° C.) to about 120° C. in the linear elastic and/ornon-super-elastic nickel-titanium alloy. The mechanical bendingproperties of such material may therefore be generally inert to theeffect of temperature over this very broad range of temperature. In someembodiments, the mechanical bending properties of the linear elasticand/or non-super-elastic nickel-titanium alloy at ambient or roomtemperature are substantially the same as the mechanical properties atbody temperature, for example, in that they do not display asuper-elastic plateau and/or flag region. In other words, across a broadtemperature range, the linear elastic and/or non-super-elasticnickel-titanium alloy maintains its linear elastic and/ornon-super-elastic characteristics and/or properties.

In some embodiments, the linear elastic and/or non-super-elasticnickel-titanium alloy may be in the range of about 50 to about 60 weightpercent nickel, with the remainder being essentially titanium. In someembodiments, the composition is in the range of about 54 to about 57weight percent nickel. In some other embodiments, a superelastic alloy,for example a superelastic nitinol can be used to achieve desiredproperties.

In at least some embodiments, portions or all of the stents or deliverysystems may also be doped with, made of, or otherwise include aradiopaque material. Radiopaque materials are generally understood to bematerials which are opaque to RF energy in the wavelength range spanningx-ray to gamma-ray (at thicknesses of <0.005″). These materials arecapable of producing a relatively dark image on a fluoroscopy screenrelative to the light image that non-radiopaque materials such as tissueproduce. This relatively bright image aids the user of the stents ordelivery systems in determining its location. Some examples ofradiopaque materials can include, but are not limited to, gold,platinum, palladium, tantalum, tungsten alloy, polymer material loadedwith a radiopaque filler, and the like. Additionally, other radiopaquemarker bands and/or coils may also be incorporated into the design ofthe stents or delivery systems to achieve the same result.

In some embodiments, a degree of Magnetic Resonance Imaging (MRI)compatibility is imparted into the stents or delivery systems. Forexample, the stents or delivery systems or portions thereof, may be madeof a material that does not substantially distort the image and createsubstantial artifacts (i.e., gaps in the image). Certain ferromagneticmaterials, for example, may not be suitable because they may createartifacts in an MRI image. The stents or delivery systems or portionsthereof, may also be made from a material that the MRI machine canimage. Some materials that exhibit these characteristics include, forexample, tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS: R30003such as ELGILOY®, PHYNOX®, and the like),nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such asMP35-N® and the like), nitinol, and the like, and others.

Some examples of suitable polymers for the stents or delivery systemsmay include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene(ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, forexample, DELRIN® available from DuPont), polyether block ester,polyurethane (for example, Polyurethane 85A), polypropylene (PP),polyvinylchloride (PVC), polyether-ester (for example, ARNITEL®available from DSM Engineering Plastics), ether or ester basedcopolymers (for example, butylene/poly(alkylene ether) phthalate and/orother polyester elastomers such as HYTREL® available from DuPont),polyamide (for example, DURETHAN® available from Bayer or CRISTAMID®available from Elf Atochem), elastomeric polyamides, blockpolyamide/ethers, polyether block amide (PEBA, for example availableunder the trade name PEBAX®), ethylene vinyl acetate copolymers (EVA),silicones, polyethylene (PE), Marlex high-density polyethylene, Marlexlow-density polyethylene, linear low density polyethylene (for exampleREXELL®), polyester, polybutylene terephthalate (PBT), polyethyleneterephthalate (PET), polytrimethylene terephthalate, polyethylenenaphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI),polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide(PPO), poly paraphenylene terephthalamide (for example, KEVLAR®),polysulfone, nylon, nylon-12 (such as GRILAMID® available from EMSAmerican Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinylalcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC),poly(styrene-b-isobutylene-b-styrene) (for example, SIBS and/or SIBS50A), polycarbonates, ionomers, biocompatible polymers, other suitablematerials, or mixtures, combinations, copolymers thereof, polymer/metalcomposites, and the like.

It should be understood that this disclosure is, in many respects, onlyillustrative. Changes may be made in details, particularly in matters ofshape, size, and arrangement of steps without exceeding the scope of thedisclosure. This may include, to the extent that it is appropriate, theuse of any of the features of one example embodiment being used in otherembodiments. The invention's scope is, of course, defined in thelanguage in which the appended claims are expressed.

What is claimed is:
 1. A stent, the stent comprising: an elongatedtubular member having a first end, a second end and an intermediateregion disposed therebetween, the elongated tubular member comprising atleast one filament; and at least one flexible tie attached to thefilament adjacent to the first end of the tubular member, the flexibletie having a first end and a second end.
 2. The stent of claim 1,wherein the first end of the flexible tie includes a first aperture andthe second end of the flexible tie includes a second aperture.
 3. Thestent of claim 2, further comprising an intermediate region disposedbetween the first aperture and the second aperture of the tie.
 4. Thestent of claim 1, wherein the flexible tie comprises a single loop. 5.The stent of claim 1, wherein the flexible tie is knotted to thefilament of the tubular member.
 6. The stent of claim 1, wherein theflexible tie is adhesively secured to the filament of the tubularmember.
 7. The stent of claim 1, wherein the at least one flexible tiecomprises two or more flexible ties.
 8. The stent of claim 1, whereinthe at least one flexible tie is biodegradable.
 9. The stent of claim 1,further comprising at least one clip configured to be secured to the atleast one flexible tie.
 10. The stent of claim 9, wherein the clipcomprises a pair of jaws configured to clamp around the at least oneflexible tie.
 11. A kit for securing a stent, the kit comprising: astent having a first end, a second end and an intermediate regiondisposed therebetween; at least one flexible tie; and at least one clip.12. The kit of claim 11, wherein the flexible tie comprises a singleloop.
 13. The kit of claim 12, wherein a first portion of the singleloop is secured to a second portion of the single loop to define a firstaperture and a second aperture.
 14. The kit of claim 11, wherein theclip comprises a pair of jaws.
 15. The kit of claim 11, wherein theflexible tie is secured to the stent adjacent to the first end of thestent.
 16. A system for reducing migration of a stent, the systemcomprising: an elongated tubular member having a first end, a second endand an intermediate region disposed therebetween, the elongated tubularmember comprising at least one woven filament; a retainer; and at leastone tie extending between the elongated tubular member and the retainer.17. The system of claim 16, wherein the retainer comprises at least oneaperture for receiving the at least one tie.
 18. The system of claim 16,wherein the at least one tie comprises a distal end including a clip,the clip configured to secure the tie to the tubular member.
 19. Thesystem of claim 18, wherein the clip comprise a pair of jaws configuredto clasp the tubular member.
 20. The system of claim 16, wherein theretainer comprises a “U”-shape.